Question 1162858
as far as i know, systems of ineqalities are solved graphically.
your inequalities are:
x + y <= 20
150x + 75y >= 3500
using the desmos.com calculator, graph the opposite of these inequalities.
you will graph:
x + y >= 20
150x + 75y <= 3500
the area of the graph that is not shaded will be your solution.
the graph looks like this.
<img src = "http://theo.x10hosting.com/2020/072701.jpg" >
you can see from the graph that the region of feasibility occurs when y is less than 0.
since both x and y have to be greater than or equal to 0, you have no solution.
a simple test will confirm this to be true.
20 * 150 = 3000.
that's the most that can be made if the number of hours has o be less than or equal to 20.